Fluorinated alkenes have long been known to control nematodes and insects when applied to the soil. U.S. Pat. No. 3,510,503, 3,654,333, and 3,780,050 all disclose such compounds. More recently, U.S. Pat. No. 4,952,580 disclosed polyhaloalkenes useful as nematocides, some of which were said to have some downward systemic activity, that is, would control to some extent nematode infestation of the root system after application to the plant foliage. The majority of the compounds disclosed by these patents are nonpolar, which is a desirable characteristic for soil-applied pesticides, providing longer effective periods, but is much less effective for foliar application to achieve systemic effects. U.S. Pat. No. 4,950,666 discloses some polar difluoroalkenylalkane compounds useful as systemic insecticides and nematocides. However, there remains a need in the art for nematode, insect, and acarid control agents having improved systemic mobility, and desirably with low effective levels of use.